Guanxinning tablet for patients who switch from dual antiplatelet therapy to aspirin alone after percutaneous coronary intervention: study protocol for a cluster randomized controlled trial

BACKGROUND: One-year dual antiplatelet therapy (DAPT), generally aspirin in combination with a P2Y12 receptor inhibitor, has been a standard treatment for patients undergoing percutaneous coronary intervention (PCI). Prolonged DAPT has proven itself effective in further reducing cardiovascular events, yet with increased risk of bleeding. Thus, it is of great necessity to find an alternative drug that is as effective but safer and more economic than the P2Y12 inhibitors after termination of one-year DAPT. METHODS: We will conduct a cluster randomized controlled trial in 3600 eligible post-PCI patients from 36 tertiary hospitals (100 patients per hospital) across mainland China. The hospitals served as clusters are randomized in a 2:1 ratio to Guanxinning tablet (GXNT) plus aspirin or aspirin alone for 12 months, with other conventional treatment applied in both groups. After the treatment period, all patients will be followed up for another 12 months. The primary outcome measure is composite cardiovascular events including cardiovascular death, non-fatal myocardial infarction, stent thrombosis, revascularization, ischemic stroke, and re-admission due to unstable angina. Secondary outcome measures are all-cause mortality, each individual component of the primary outcome measure, and stopping or reducing the rate of nitroglycerin administration. Adverse events, including bleeding, will be closely monitored during the whole trial period. In addition, a cost-effectiveness study of GXNT for the study population will be conducted along with this trial. DISCUSSION: This trial aims to determine whether the addition of GXNT will further improve prognosis without increasing bleeding risk for patients with coronary artery disease who have switched from DAPT to aspirin alone after PCI. Completion of this clinical trial might provide a novel, promising, and safer alternative to P2Y12 inhibitors for prolonged antiplatelet therapy in post-PCI patients. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IIR-17010688 . Registered on 20 February 2017.